The work happening in the script I'm showing today is only possible if you use the new Make2D component that comes with the work in progress version of Rhino 6. The developers at McNeel allow Rhino 5 users with a paid license to access the work-in-progress build of Rhino 6 (Windows only). If you have a license key you can access the WIP build here: https://www.rhino3d.com/download/rhino/wip
The new Make2D component means you can work in Rhino and see a real-time update of the Make2D function without having to re-run "Make2D" in Rhino each time you want to export linework. This script will be critical in an upcoming tutorial that explains how to take the linework from the Make2D component and bring it into Illustrator without having to save and export Illustrator files.
The script relies on Grasshopper's Geometry Pipeline which automatically selects all geometry with either a given name or a given layer. This component is extremely useful since it allows the user to just have the script running in the background in Grasshopper and work solely in Rhino, but still have Grasshopper doing all the work in the script.
For the script to work, you have to have saved a Named View that will determine the camera positioning for the Make2D, and type that name into the first yellow panel (mine is called "View1"). Have a look at the script I've attached and some of various components involved.